In recent years, there has been an increasing number of applications for displaying a single image on a large screen by multi-tiling, in which a plurality of image display devices such as liquid crystal display devices are combined (Patent Document 1). In such applications, there are not only still images, but also numerous cases of displaying moving images. When performing moving image display in this kind of multi-tiling, at the interface of the image display devices that are connected side by side in the vertical direction, there is the problem of misalignment occurring between the image display device on the upper side and the image display device on the lower side.